Quote:
Originally Posted by Dennis
Hi Gary
This particular line really stopped me in my tracks:
"While the Hubble Constant is constant everywhere in space at a given time, it is not constant in time. So, when we are comparing the Hubble Constants that come out of various techniques, we are comparing the early universe (using distant observations) vs. the late, more modern part of the universe (using local, nearby observations).”
When taking Physics classes at school we performed several experiments that involved measure various (less esoteric) constants and I was always puzzled by how many "Constants" there were.
In an abstract sense, if some "thing" is "Constant", meaning non-changing, immutable, ever the same, etc. then "it" should not have a "beginning".
Otherwise when it "started" it must have changed from "not existing" to "now existing", which is a "change", so it cannot be a "Constant".
Needless to say this is adult life contemplation, not from my school boy days.
Cheers
Dennis
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Hi Dennis,
It's pretty funny isn't it?
The Hubble Constant had long been believed to be a constant but
as it transpires it appears not to be. It will at least have a first
differential with respect time.
It's how Brian Schmitt along with Saul Perlmutter and Adam Riess
won their Nobel Prizes. They observed that not only will the universe
continue to expand but the rate of expansion is increasing with time.
So depending on how far away you observe and therefore how far
back in time you observe, you get a different value for the Hubble
Constant.
8 million Swedish Krona and an almost certain Nobel Prize in Physics
will go to the first person who can explain why that is so.